RU2067662C1 - Method for extracting petroleum from petroleum tank (options) - Google Patents

Abstract

FIELD: petroleum extraction. SUBSTANCE: nutritive matters are injected to the tank for endogenic microorganisms being inside. The nutritive matters are hold inside the tank for the time and under conditions being adequate for exhausting at least one nutritive matter, and the petroleum is extracted. Glucose free carbon source is used as the nutritive matter. The nutritive matters are injected with water or petroleum. EFFECT: more complete petroleum extraction. 13 cl, 2 dwg, 13 tbl

Description

 The invention relates to methods for extracting oil from an oil reservoir, involving the use of endogenous microorganisms for enhanced oil production from the reservoir.

 During primary oil production, the pressure in the reservoir decreases and, accordingly, oil production decreases. To compensate for this reduction process, water or gas is injected into the tank. This process is referred to as the so-called secondary oil production.

 The water-oil ratio is increased until secondary oil production is economically viable. Residual oil up to 65% of the initial oil content in the reservoir (001Р) is distributed in structures significantly different from 001Р. The inability during the secondary oil recovery of residual oil is due to the presence of capillary forces in the oil-water-rock system and the inability of the introduced fluids to penetrate parts of the reservoir formation. Surfactants are used to lower the inter-surface tension between the reservoir fluids and the residual oil, so that oil that cannot be removed with the injected fluid alone is displaced.

 Surfactants used in enhanced chemical oil production show optimal activity in a narrow range of temperatures, hydrophobic-lipophilic equilibrium values, mineralization, and rock types.

 Thus, enhanced refining processes using surfactants have generally been developed for specific reservoirs.

 It has been shown that surfactants based on crude oil (for example, petroleum sulfonates) in semi-industrial tests lead to desorption of residual oil, but at a price significantly higher than the market price of oil extracted in this way. Surfactants are expensive in themselves; they tend to be adsorbed on the rock, which is why they are needed in large quantities.

 Polymers are also successfully used, but again at an expensive price. Polyacrylamide is used, obtained both from crude oil and from microbial products of xanthihydrol resins; the first is less expensive, but ineffective at high temperatures and levels of mineralization, common to many tanks. The latter is more acceptable, although there are problems with the formation of microgels that cause blocking on the injection surface, destruction can occur in the tank, the cost of the material is significant.

 It is proposed to use surfactants formed by microorganisms for enhanced oil production. This technology is known as microbial enhanced oil production.

 The production of surfactants using microorganisms has been known for many years. These biological surfactants almost always contain a lipid component and are usually glycolipids. Other classes of biological surfactants include lipopeptides, phospholipids, fatty acids and neutral lipids.

 There are a number of potential advantages in using microbial extraction processes, including an extensive series of compounds with properties useful for enhanced oil production that can be obtained by microbial biosynthesis; the cost and ability to produce biometabolites inside the tank with a decrease in the amount of chemical surfactants as a result.

 Advanced microbial enhanced oil production involves introducing and maintaining an exogenous microbial population in an oil reservoir. This population is supplied with nutrients such as molasses, or other fermentable sugars, sources of nitrogen and mineral salts in the form of additives to the flow of water used for the secondary displacement of oil.

 Other hydrocarbon substrates were investigated, but the economic advantage of fermentable sugars made them more preferred.

 The development of methods involving the introduction of microorganisms into oil tanks was limited by the conditions existing in them.

 In particular, small and variable pore sizes, along with extremely high temperatures, mineralization-ionic forces, pressure, severely limit the strains, microareal and the number of microorganisms that can be introduced.

 In addition, the environment in many tanks is highly restored. The lack of oxygen strictly limits a number of biometabolites that can be synthesized by microorganisms introduced into the reservoir.

 The disadvantages of using microorganisms in modern microbial enhanced oil production technology are that they can be prone to occluding (clogging) reservoir pores due to the large volume of cells caused by the rich nutritional conditions created in the water stream.

 In addition, these large microbial bodies are difficult to penetrate into the small pores of the rock.

 For these reasons, prior art technical solutions in this area (for example, US patent NN 4,475,590 (Brown), 4,971,151 (Shihi)) do not provide a sufficiently effective microbial enhanced oil production.

 It was unexpectedly found that the surface-active properties of microorganisms adapted to growth in oil wells can be significantly enhanced if, following the growth of microorganisms, nutrient depletion occurs. The effect of enhanced oil production according to the invention is also explained as follows. Typically, microorganisms in an oil tank are located in a medium containing virtually no nutrients, at the interface between the oil and water phases. With the addition of nutrients, the growth of microorganisms occurs, but then the depletion of nutrients occurs and this enhances the detergent properties of microorganisms to the limit.

 The cell volume of microorganisms obtained by depletion of nutrients is much less than the cell volume of microorganisms that received enough nutrients. A 70% reduction in cell volume is common. The reduced cell volume allows small microorganisms to penetrate better into the pores of the rocks, which, combined with the surface-active properties of the microorganisms, provides enhanced oil recovery from the reservoir.

 The invention provides for the use of a non-glucose carbon source in a nutrient medium, which is very important to achieve the desired effect. It was found that compounds containing glucose units, for example, molasses, do not improve the surface-active properties of microorganisms. The nutritional value of glucose and glucose-containing compounds in this situation is excessive and only increases the population of microorganisms of large cell volume.

 Accordingly, according to one aspect of the present invention, there is provided a method for extracting oil from an oil reservoir, comprising introducing into the reservoir nutrients for endogenous microorganisms located in the reservoir, maintaining the reservoir with nutrients and oil, and recovering the oil, wherein non-glucose carbon sources are used as nutrients and the aging of the tank is carried out over time and under conditions sufficient for significant depletion of at least about Foot of the added nutrients.

 Peptone or protein and / or their processed products, or extractants, or their sources are preferably used as a non-glucose carbon source.

 Local microorganisms are preferably used as endogenous microorganisms, but additional introduction of exogenous microorganisms into the reservoir is also possible.

 Microorganisms, exogenous or endogenous, as well as nutrients, are preferably introduced into the reservoir in water or in oil.

 All operations are preferably carried out under anaerobic conditions.

 In an embodiment of the aforementioned method, it is provided that water is introduced into the tank cyclically, wherein at the stage of the first cycle, nutrients and / or exogenous microorganisms are added to the water, followed by the introduction of water into the tank, withstand water in the tank for a time and under conditions sufficient oil extraction, and water is extracted from the extracted oil, and at the stage of the second cycle, the content of nutrients and / or microorganisms in the water is preferably determined, their concentration is adjusted to the required imogo level and re-introduced into the water in the tank.

 Another aspect of the present invention relates to a method for extracting oil from an oil reservoir, comprising placing microorganisms in a nutrient medium, keeping microorganisms in a nutrient medium, and extracting oil, and previously, before placing microorganisms in a nutrient medium, microorganisms are removed from the reservoir or other source that can be adapted to the conditions of the oil reservoir, microorganisms are kept in a nutrient medium for a time and in conditions sufficient for substantial depletion of at least one of the components of the nutrient medium, after which the microorganisms are introduced into the reservoir. Here, non-glucose sources of carbon are also used as a nutrient medium, preferably as described above.

 Another aspect of the invention relates to a method for extracting oil from an oil reservoir, comprising introducing into the reservoir nutrients for endogenous microorganisms located in the reservoir, maintaining the reservoir with nutrients and oil and extracting oil, wherein endogenous microorganisms are preliminarily removed from the reservoir, and the isolated microorganisms are grown under conditions sufficient to increase their population, followed by their restriction in nutrients, leading to a decrease in their cells volume to a level compatible with the introduction into the reservoir, while non-glucose sources of carbon are used as nutrients, and the reservoir with microorganisms is kept for a period of time and under conditions sufficient to deplete at least one of the nutrients.

 And the last aspect of the invention relates to a method for extracting oil from an oil reservoir, according to which the nutrients for the endogenous microorganisms present in the reservoir are introduced into the reservoir, the nutrient reservoir is kept and the oil is recovered, wherein at least one anaerobically degraded non-glucose source is used as nutrients carbon and at least one organic molecule, and holding the tank is carried out over time and under conditions sufficient accurate for significant depletion of at least one of the added nutrients, while depletion is controlled by time or by increasing the population of endogenous microorganisms.

The invention is further described in more detail with reference to the accompanying illustrations, which show:
FIG. 1 graphic representation of oil production in barrels per day [BRD (+)] at the Alton 3 well after injection of process water without nutrients,
FIG. 2 is a graphical representation of oil production in barrels per day [BRD (+)] of an Alton 3 well after injection of process water with nutrients.

 First of all, a sample of microorganisms is removed along with a sample of liquid from the reservoir in which microorganisms live, in order to determine the probability of growth restriction due to depletion of nutrients by analyzing a liquid sample.

 The term "nutrients" is used in its broadest sense and includes inorganic and organic compounds necessary for the microorganism to grow or to promote their growth.

 Inorganic compounds contemplated herein include those that contain at least one of the following elements: C, H, P, N, Mg, Fe, or Ca.

By way of example only, such inorganic compounds include: PO $\genfrac{}{}{0ex}{}{\text{2-}}{\text{4}}$ NH $\genfrac{}{}{0ex}{}{\text{+}}{\text{4}}$ NO $\genfrac{}{}{0ex}{}{\text{-}}{\text{2}}$ NO $\genfrac{}{}{0ex}{}{\text{-}}{\text{3}}$ and SO $\genfrac{}{}{0ex}{}{\text{2-}}{\text{4}}$ among the others. Once determined nutrient (s) (o) are then added to the reservoir over time and under conditions conducive to the growth of endogenous microorganisms. Sampling also determines the amount of digested organic carbon.

 More specifically, a sample from the reservoir, after introducing a limiting nutrient into it, is taken in order to determine the possibility of growth of the endogenous organism and to obtain carbon and energy from endogenous organic compounds.

 Standard methods such as spectrophotometry, N.M.P. are used to determine the carbon contained in the compounds. infrared, HPLC, gas chromatography, chemical tests, etc.

 If necessary, the carbon source is supplied with a limiting nutrient. In a preferred embodiment, a non-glucose carbon substance is used, as glucose and compounds including glucose units (e.g. molasses) did not show an increase in the surface-active properties of endogenous microorganisms after their growth on such compounds. An example of the present non-glucose carbon source is peptone and the like.

 Further, an adjustment may be made depending on the number of microorganisms present. If there are a large number of microorganisms, it is possible to introduce the missing nutrients directly into the reservoir to stimulate growth over a period of time. On the other hand, if the population of microorganisms is small, it can be increased where conditions permit, in the laboratory or in a suitable environment where the missing nutrients are supplied to increase their quantity.

 This is especially preferred if the microorganisms are subjected to more than one cycle in which nutrients are added to effect growth, followed by exposure to the microorganisms under conditions in which nutrients are again deficient.

 After this procedure, microorganisms are introduced into the reservoir. During each of the aforementioned growth stimulation and suppression cycles, an analysis can be performed to determine if microorganisms are in a state of growth.

 Analysis of the configuration of fatty acids using HPLC or GLC is especially convenient for determining the degree of saturation and cis-trans configuration of membrane lipids have changes, because growth slows in response to nutrient restriction.

 Known methods for enhanced oil production using microorganisms were created on the assumption that some strains of microorganisms are more suitable for the production of surfactants than others, and the only necessary requirement is the isolation of strains that efficiently produce surfactants from all other microorganisms .

 On the contrary, the present invention is based on the fact that the properties of surfactants are inherent or induced characteristics of microorganisms living inside the oil reservoir, and that their surface-active properties depend on the physical state of the microorganisms themselves.

 Therefore, by the term “surface active property” is meant a property of a microorganism that reduces surface tension, and this property may be endogenous or exogenous to the cell and may include the production of surfactants.

 Microorganisms can not only have surface properties, but can cause gas formation, which can contribute to oil production. In addition, in the known methods, the introduced microorganisms may not be very suitable for survival in a particular medium of a separate tank, since the medium of the tanks varies greatly in temperature, pressure, pH, etc. Thus, the prospects for the successful spread of microorganisms in the tank are not high.

 In an aspect of the invention using microorganisms already living in the reservoir, it is initially known that they are able to survive in the reservoir environment and can be introduced into the reservoir without the risk of harmful exogenous effects caused by exogenous microorganisms.

 Also, as a rule, microorganisms inside the oil reservoir are in a state of lack of nutrients, since the conditions in the oil reservoirs are usually unfavorable for the growth of populations of microorganisms. Microorganisms are located at the separation of the two water-oil phases inside the reservoir and are physically localized around that boundary, respectively, whether they need nutrients or not.

 When studying the conditions of nutrient deficiency, it was found that microorganisms become more hydrophobic. On the other hand, it is possible that under this condition the microorganism will produce and secrete surfactants, or the cells themselves will be able to take a hydrophobic character or qualities similar to surface-active properties. Thus, directly viable cells of microorganisms that are at rest or possibly after the death of microorganisms exhibit the properties of surfactants.

In the event that numerous microorganisms are found in the sample taken from the oil reservoir (for example, more than 10 ³ cells per 1 ml), it is assumed that there are sufficient microorganisms in the reservoir to ensure appropriate production of surfactants.

 In this case, nutrients are fed into the reservoir that limit the growth of microbes, after which the microorganisms undergo at least one cycle of restriction in nutrients, as a result of which the surface-active activity of the microorganisms increases and oil production increases.

 According to the invention, in a method in which microorganisms are taken from an oil reservoir and subsequently returned to it to facilitate oil production, sampling can be carried out in any convenient way. Typically, a sample is taken from a reservoir directly through a well. The sample contains a water-oil reservoir formation along with microorganisms. The extracted sample is analyzed by methods known to those skilled in the art, for example, atomic absorption spectrophotometry, in order to determine the nutrient (s) (o) that obviously limit the growth of microbial cells.

 Typically, such an analysis will show the absence of nitrogen in the form of nitrates and the absence of phosphates. Microorganisms are then grown by adding predefined missing ingredients to the culture medium.

 It is possible to determine the growth of microorganisms in a number of media and choose the medium that provides maximum bacterial growth for the culture of protozoa.

 During the growth of microorganisms, samples are taken and their surface-active properties are checked. For example, a test can be carried out to determine their ability to reduce surface tension and a double comparison chart can be drawn up showing the relationship between the depletion of nutrients and the final surface-active properties of the microbial body.

 The depletion of nutrients can also occur naturally, as they are consumed due to microbial metabolism, or by taking and transferring them to another medium originally taken from the reservoir.

 Typically, microorganisms are subjected to several cycles of addition and depletion of nutrients until the surface-active properties, which can be established by measuring the decrease in inter-surface tension caused by the microorganism, are increased to the limit.

 As soon as the required number of microorganisms is produced, the destruction of which is sufficient to give the optimum effect in terms of reducing surface tension, the microorganisms are introduced into the oil tank.

 Microorganisms can be introduced directly through the well, after which they spread throughout the tank. Microorganisms penetrate the pores of the rock, acting as surfactants to allow the trapped oil in the rock material to be washed out of the well leaving the well.

 As noted above, microorganisms that have undergone nutrition and depletion cycles have significantly smaller cell sizes than microorganisms that have only undergone nutrition. It is common to reduce cell volume by 70%. In addition, such microorganisms may have a smaller cell volume than the volume of microorganisms from a well that has not undergone such treatment.

 Small-sized microorganisms are able to penetrate through the pores, which, together with the surface-active properties of microorganisms, facilitates oil production.

 Microbes that have surface-active properties and are able to survive in the conditions of the oil reservoir, but which are not adapted to the conditions of the specific reservoir where they are introduced, can be subjected to nutrition-depletion cycles to improve their surface-active properties according to the invention.

 Such microorganisms can then be introduced into the oil well to expand oil production.

 In accordance with the present invention, it was unexpectedly found that process water can be an adequate water base into which the required nutrients and / or microorganisms can be added before they are introduced into the tank.

 By the definition of "process (or" product ") water" is meant the aqueous phase of a water-oil mixture isolated from a reservoir. Process water may be by-produced water. The product water is buffered so that it is compatible with the ecology of the tank; carbonates and bicarbonates are often used to create buffering conditions.

 The choice of a buffer compound depends on the environmental pH of the tank, which can actually be in the range of pH 2-10.

 Preferably, the required nutrients, possibly including a carbon source and / or exogenous microorganisms, are added to the product water and introduced into the tank under conditions and for a time sufficient in accordance with the invention.

 The recovered water-oil mixture is collected and separated into phases. The aqueous phase is collected and analyzed for the concentration of nutrient (s) (c), carbon source and / or microorganisms originally contained therein.

 If necessary, the concentration of these components is adjusted accordingly, also adjusting the buffering ability of the phase water before the product is introduced into the tank, where the cycle is repeated.

 In accordance with the invention, in addition, it was found that the order in which the components are introduced into the product water significantly affects the final result. Therefore, it is advisable to test the tanks individually using sand and product water, the components of which are listed in Example 3 (Kastenholz medium).

 The term "reservoir" referred to here means any place of occurrence. In addition to the concept of “oil production method”, this includes the practice of standard oil production, not limited to the use of water or gas to pump pressure.

 Further details of the methods of the invention, providing activation of the surface-active properties of microorganisms and oil production using cultures of microorganisms and oil production using cultures of microorganisms, are given in the following non-limiting examples.

 Example 1. This example demonstrates a sharp decrease in surface tension (lT), which can be achieved by applying cycles of nutrient enrichment and depletion of the nutrient medium.

 Surface tension is measured in millinewtons per meter.

 A culture of Acineto bacter cocloaceticus with undetectable surface-active properties is placed in the nutrient broth NB 1/2 fortress with paraffin and without it. The nutrient broth NB 1/2 fortress, as was found in previous experiments, is optimal for the depletion of nutrients and the production of surface activity.

All cultures are incubated at a temperature of 32 ^o C until morning. Then, the surface tension of the medium is measured in comparison with hexadecane using the drop formation method at 24, 48 and 96-hour incubations (see Table 6).

 A culture of 1/2 NB is then subcultured in fresh medium and the test repeated (see table. 7).

 This phenomenon was reproduced using a number of mesophilic and thermophilic bacterial strains, including Psedomonas aeruginosa, Pseudomonas fluorescens, Bacillus acilocaldarius, Thermus thermophilys and Thermophilus and Thermus aquaticus.

Example 2. This example demonstrate the effect of a hydrocarbon, in this case paraffin, on a decrease in surface tension. The Thermus aquaticus culture was inoculated into Castenholz medium (Castenholz. RW (1969) Bacteriol. Rev. 33, 476). One tube from each culture pair is coated with paraffin. The cultures are then incubated at 70 ^° C. and the surface tension is measured compared to hexane using the drop formation method (see table 8).

 The cultures with the lowest surface tension are subcultured on fresh medium and subjected to three more cycles of nutrition and depletion. The results for the fourth cycle of nutrient depletion are presented in table. 9.

 Example 3. This example describes studies of samples of water-oil formations taken from the Alton oil well in the Surat Basin of the Southern Kingdom of Australia.

 Protocol for a sample study of reservoir fluids.

 I. Samples for microbiological studies.

The main tasks were to take a sample of the formation presented in reservoir fluids, to minimize contact of the sample with air. Thus, Alton samples were taken at the wellhead using the following protocol:
1). A sample was taken in 50 ml plastic standard syringes. The syringes were completely filled with the sample so that air did not enter during suction.

 2). The needle on the syringe with the sample was inserted through the rubber gasket of the flask containing 0.1% diaresorcinol (redox indicator).

 3). A second needle (B) was inserted directly through the pad.

 4). The reservoir liquids were introduced into the sample flask until they were sprayed through the needle. When this happened, the needle was quickly removed. Then the syringe with the needle was removed.

5). In all samples that remained pink for more than 30 minutes, 0.2 ml aliquots of 10% Na ₂ • 9H ₂ O were added until the solution became colorless.

 6). Samples were immediately transported to the laboratory for analysis.

 II. Samples for chemical research.

 Samples for chemical analysis were taken in accordance with standard methods, for example Collins A.G. (1975) Geochemistry of oilfield Waters. Developments in science series N 1, Elsevier Scientific Publishing Company, New York.

Initial Sample Rating:
I. Microbiological assessment
Microorganisms in samples containing oil and water were examined using a phase microscope and dyes, such as GRAM. Various microorganisms were considered, including a number of highly mobile forms. Samples were grouped according to differences in morphological and staining characteristics. The predominant forms were two different bacteria; the first was relatively shorter and wider than the second. Short bacteria had bloated sections, especially at their ends, longer bacteria sometimes formed short chains or clusters.

 The third type of unicellular was short gram-positive cocci. The number of bacteria that could be observed was proportional to the amount of oil in the test sample.

 II. Chemical analysis.

 The chemical nature of the water from the oil reservoir was assessed using a series of analyzes of water and oil samples. These analyzes were performed using standard techniques, for example, Collins A.G. (1975) Geochemistry of oilfield Waters Developments in science series No. 1, Elsevier Scientific Publishing Company, New York American Petroleum Institute (1986). These techniques include atomic spectrophotometry (AAS), flame photometry and the use of selective ion electrodes, recommended for the analysis of water in an oil field.

 Selected analysis results are presented in table. 10.

 It was concluded that these results are also quite typical for fresh artesian water obtained in hower-Cretaceous Iurassic aquifers in the Surat Basin region surrounding the Alton well.

 The composition of the medium for bacterial growth.

The ability of several carbon sources to increase the growth of microbes in oil-water samples has been investigated. This included a change in lactate, acetate, propionate, palmitate, benzoate, formic acid salt, hexadecene, a mixture of C ₄ C ₆ C ₈ , as well as H ₂ / CO ₂ / acetate.

 None of the proven carbon sources provided bacterial cell growth. Based on these results and the results of chemical analyzes of Alton water samples, it was concluded that nitrates and phosphates, which are potentially essential nutrients, were almost completely depleted.

 A series of experiments was undertaken to determine the effect of periodic addition and depletion of nutrients on the occurrence of surface-active characteristics. At the same time, it was studied whether the addition of established bacterial growth stimulants, such as peptone and yeast extract, would increase surface activity.

 Finally, a medium exhibiting potentially desirable properties was tested for the extraction of Altona oil from a porous material.

 The initial growth medium.

 The composition of the initial growth medium was based on the results of chemical analyzes and previous observations that the bacteria in the Alton reservoir need bicarbonate / carbonate buffering.

 Materials and methods.

 A 125 ml Wheaton flask was filled with 25 ml of oil and 75 ml of test medium. Then the flasks were sealed. Sterilized Alton oil samples were inoculated into non-fortified media as a control. The composition of the main medium and additives are shown in table. 1.

 From these components, 4 culture media and a control were prepared. All culture media and the control group contained basic medium and sodium carbonate. Additives are shown in table. 2.

Of all the flasks, oxygen was chemically removed using 0.5 ml of a 0.5% sodium sulfide solution, and then their anaerobicity was checked in the presence of reduced 0.1% diazoresorcinol. An incubation temperature of about 72 ^o C was established, which approximately corresponded to the temperature in the tank Alton.

 The growth and surface tension of the samples were monitored daily. Growth was measured semi-quantitatively using a microscope. Surface tension was measured compared to hexadecane using the drop formation method (Harkine M.E. and Brown B (1919) I. Amer, Chem, Soc. Il p. 499). This method involves expelling a sample from a syringe in a hexadecane solution. The volume of fluid required to form the droplet is established and surface tension is measured using standard formulas.

 Results.

 In the studied media, no noticeable differences in semiquantitative growth were found (see Table 3).

 The resulting picture is generally consistent with the depleted state after the initial inoculation (lag phase, first week), followed by a period of active growth (exponential phase, week 2).

 A further state of exhaustion occurs with subsequent proliferation (stationary phase, weeks 3 and 4). Wednesdays 1 and 2 were very rich. Therefore, the depletion of nutrients in them occurred only partially in the 4th week.

 Conclusions.

 1). The addition of yeast extract worsened the decrease in surface tension in a given time period.

 2). The addition of a solution with trace elements did not lead to either an increase in microbial growth or a decrease in surface tension.

 As a result of these experiments, Wednesday 4 was chosen for oil production experiments.

 Oil recovery from compacted sand.

 The extraction of residual oil from compacted sand was investigated as follows.

 Materials

Sand: May Baker, Batch MX 6210, acid washed, medium fine, sterilized for 10 hours at 170 ^° C. A grain size of not more than 35% passes through a 300 micron sieve and not more than 20% passes through a 150 micron sieve .

Sand / oil mixture: 5 ml of oil per 34 g of sand
Wednesday: Wednesday 4 (as above)
Test tubes: Pyrex 9827
Traffic jams: "Subasil" N 33 + wire twists.

 Methods

 1. A mixture of sand-oil. Sand and oil are mixed in one tank using 5 ml of oil per 34 g of sand. The sand-oil ratio was set in advance by washing the sand with water until no residual oil was recovered. The sand-oil mixture in the tubes was compacted using an ultrasonic bath for 10 minutes.

 2. A mixture in an amount equivalent to 5 ml of oil and 34 g of sand was added to each tube. Moreover, 22 ml of medium No. 4, with and without carbonate, was added to each tube. The tubes were closed, the tubes were fixed in a knot.

3. All tubes were incubated at 72 ^° C. in an air oven.

 4. The amount of oil recovered from compacted sand was determined by the difference in weight of the tube after all the oil on the surface of the water was collected by syringe.

 5. At the end of the experiment, the amount of oil remaining in the sand was checked by extraction with an organic solvent containing 87% chloroform and 13% methanol in a Soxhlet apparatus.

 The results are presented in table. 4.

 Discussion.

 Since the microbiological increase in oil recovery using medium No. 4 turned out to be equivalent to that achieved using a commercial surfactant, this medium was accepted for final testing.

 High pressure and high temperature experiments.

 The last phase of the preliminary experimentation was the analysis of oil production under conditions simulating an Alton reservoir.

 Materials and methods.

 The extraction of residual oil under conditions similar to those existing in the Alton reservoir was investigated using an apparatus specially designed for this purpose. It contains a metal tube inside a water jacket. The tube was packed with porous material and the sample was sealed. The temperature was maintained by a circulation system into which water was supplied through a silicone oil bath, and then around the tube through a water jacket.

A temperature of 73 ^° C. was maintained by a thermostat.

 An initial pressure of about 5000 kPa was created by a Haskell hydraulic pump.

 1. Oil and sand, as described above, were mixed until there was an excess of oil. This mixture was allowed to drain and packaged in a stainless steel column. Then the column was placed in the center of the zone of high temperature and high pressure. After that, pressure is applied to the column and the temperature is increased.

 2. Once the column packed with sand-oil was balanced, it was washed with water at regular intervals. Washing was repeated until oil was removed from the column.

 3. Medium No. 4, which was modified to simulate the chemical equilibrium existing in the Alton reservoir, was introduced into the column until it completely replaced water. Then the column was hermetically sealed and the appropriate temperature and pressure were maintained.

 4. Samples were taken from the column and the recovered oil was studied. At the same time, the nutritional state of the bacteria was tested and the washing with the nutrient mixture was repeated or not, depending on the test result.

 If during this process the residual oil was not displaced, then a culture enriched in the bacteria of the Alton reservoir, which were added prior to depletion under laboratory conditions, was inoculated into the column. The column was removed and steps 4 and 5 were repeated until further residual oil ceased to be extracted.

 Wednesday.

 The medium used in this experiment contained the product water of the Alton reservoir with the following chemical additives (see table 11).

Solution A was mixed with solution B, adjusted to pH 8.4 using either concentrated hydrochloric acid or magnesium carbonate. Then peptone was added. This medium was sterilized by filtration and then heated to 73 ^° C. before washing the column with it.

 Results.

 The sand-oil mixture included 751 g of sand and 123 ml of oil. In the process of washing with water, 98 ml of oil was regenerated. Nutrient irrigation was performed after 2 weeks (see table. 5).

 Oil remaining in the column: 123-98 = 25 ml.

Oil recovered: 6 ml
Additionally recovered residual oil: 24%
Example 4a

 The results of the control field tests of product water without nutrients are given below. Field trials were conducted at the Alton well (Queensland, Australia). The results are presented graphically (Fig. 1) and clearly show that after the closure in September 1988, product water alone did not lead to an increase in oil production.

 Example 4b Field trials were conducted as shown below and included the use of product water with nutrients. The results are shown in FIG. 2.

 In general, buffered product water containing the nutrients specified in Example 3 was injected into the field and the well was shut for up to 3 weeks.

 By the end of this period, the well was exploited further and tested for oil production.

 Introduction program 2 a) The well condition is presented in table. 12.

 The kit ended at 5997.64 ft RKB.

 After the well-known steps necessary to prepare the well for introducing the required fluid into it, about 53 barrels of nutrient water solution and about 35 barrels of product water were injected at a speed of 0.5 barre / min at a pressure of 2200 psig.

 A total of 15 thousand liters (94.3 barrels) of nutrient solution was prepared. Given a 7% loss in the form of residues at the bottom of the tank, this gives 86 barrels of injected solution; moreover, 25 barrels were injected into the well during the optimization of the nutrient mixture, and the rest was injected for about 3 hours after 9-12 hours in air and subsequent pH adjustment.

 All liquid introduced into the field was filtered through 28 and 10 micron filters.

Power Balancing Pump
Casing production column 7 "outside diameter (full column)
From the bottom to the head 2 (nozzle) 26 J-55 37 jts 29 N-80 43 jts 23 S-95 87 jts 26 J-55
Pipes for the operation of wells 2-7 / 8 ", 6.5 ppf J-55 grade
Cut lining 6032-6063 ft. RKB 6073-6104 ft. Rkb
The total depth of the rear plug is 6109 ft. Rkb
b) Well closure sequence.

 1. Replace the ring. To fasten. Install a stop line on the side of the annular hole. Lock the well using drilling water.

 2. Remove the pump. Pull out the piston rod of the pump.

 3. Close the "Christmas tree". Install pipe plungers (BOP C / W 2-7 / 8 ").

 4. Remove the anchor tube and RlH with a 2-7 / 8 "column to confirm the presence or absence of filling at the bottom.

 Note: The latest development kit (VNA) was as follows (from bottom to head).

 Then the well was returned to production and after a certain time, the extraction of oil from it was resumed.

 Results.

 The closure was carried out on January 26, 1989, and the opening on February 17, 1989.

 The following results were obtained (see table. 13).

 The results undoubtedly demonstrate enhanced oil production from the reservoir.

 The above detailed examples of the operations of the methods of the invention are understood by those skilled in the art and can be used to illustrate any of the four aspects of the invention. Obviously, the technological chains of methods for each aspect of the invention have fundamental differences only in the sequence of operations described above (sampling, analysis, introduction of nutrients, depletion, aging and oil recovery), therefore, based on the above description, it will not be difficult for a specialist to present a complete picture of the implementation of any of the variants of the invention indicated in the claims and described here after the description of the prior art.

 The above examples are not limiting, and it is clear that various modifications of the invention are possible without departing from the idea of the invention or leaving its scope defined solely by the claims.

Claims (13)

 1. A method of extracting oil from an oil reservoir, including introducing into the reservoir nutrients for endogenous microorganisms located in the reservoir, maintaining the reservoir with nutrients and oil and extracting oil, characterized in that non-glucose sources of carbon are used as nutrients, and aging of the reservoir carried out over time and under conditions sufficient to substantially deplete at least one of the added nutrients.  2. The method according to p. 1, characterized in that peptone or protein and / or their processed products, or extractants, or their sources are used as a non-glucose carbon source.  3. The method according to p. 1, characterized in that the local microorganisms are used as endogenous microorganisms.  4. The method according to p. 1, characterized in that in addition to the tank enter exogenous microorganisms.  5. The method according to p. 1, characterized in that the nutrients are introduced into the tank in water or oil.  6. The method according to p. 1, characterized in that all operations are carried out under anaerobic conditions.  7. The method according to p. 1, characterized in that use anaerobically degradable non-glucose source of carbon.  8. The method according to p. 4, characterized in that the exogenous microorganisms are introduced into the tank in water or oil.  9. The method according to PP. 5 and 8, characterized in that the water is introduced into the tank cyclically, and at the stage of the first cycle, nutrients and / or exogenous microorganisms are added to the water, followed by the introduction of water into the tank, withstand the water in the tank for a time and under conditions sufficient for oil extraction, and water is extracted from the extracted oil, at the stage of the second cycle, it is preferable to determine the content of nutrients and / or microorganisms in the water, bring their concentration to the required level and re-enter the water into the reserve al.  10. A method of extracting oil from an oil reservoir, comprising placing microorganisms in a nutrient medium, keeping microorganisms in a nutrient medium, and extracting oil, characterized in that before placing microorganisms in a nutrient medium, microorganisms are removed from the reservoir or other source that can be adapted to conditions oil tank, the holding of microorganisms in a nutrient medium is carried out over time and in conditions sufficient for significant depletion of at least at least one of the components of the nutrient medium, after which microorganisms are introduced into the reservoir, and non-glucose sources of carbon are used as the nutrient medium.  11. The method according to p. 10, characterized in that peptone or protein and / or their processed products, or extractants, or their sources are used as a non-glucose carbon source.  12. A method of extracting oil from an oil tank, including introducing into the tank nutrients for endogenous microorganisms located in the tank, keeping the tank with nutrients and oil for a certain time and extracting oil, characterized in that the endogenous microorganisms are preliminarily removed from the tank, grown isolated microorganisms under conditions sufficient to increase the growth of their population, followed by their restriction in nutrients, leading to a decrease letochnogo volume to a level compatible with the introduction into the tank, and as a nutrient use non-glucose carbon sources, and maintaining the tank with the microorganisms is carried out for a time and under conditions sufficient to deplete at least one of the nutrients.  13. A method of extracting oil from an oil reservoir, including introducing into the reservoir nutrients for endogenous microorganisms in the reservoir, maintaining the reservoir with nutrients and recovering the oil, characterized in that at least one anaerobically degraded non-glucose carbon source is used as nutrients and at least one organic molecule, and the aging of the reservoir is carried out over time and under conditions sufficient for significant depletion at extremely least one of the added nutrients, the depletion control by time or by increasing the population of endogenous microorganisms.

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